1.EventLoop的类关系图

2. EventExecutor

    /**
     * 返回自身的对象
     * Returns a reference to itself.
     */
    @Override
    EventExecutor next();

    /**
     * 获取所属的EventExecutorGroup
     * Return the {@link EventExecutorGroup} which is the parent of this {@link EventExecutor},
     */
    EventExecutorGroup parent();

    /**
     * 当前线程是否在 EventLoop 线程中
     * Calls {@link #inEventLoop(Thread)} with {@link Thread#currentThread()} as argument
     */
    boolean inEventLoop();

    /**
     * 指定线程是否是 EventLoop 线程
     * Return {@code true} if the given {@link Thread} is executed in the event loop,
     * {@code false} otherwise.
     */
    boolean inEventLoop(Thread thread);

    /**
     * 创建一个 Promise 对象
     * Return a new {@link Promise}.
     */
    <V> Promise<V> newPromise();

    /**
     * 创建一个 ProgressivePromise 对象
     * Create a new {@link ProgressivePromise}.
     */
    <V> ProgressivePromise<V> newProgressivePromise();

    /**
     * 创建成功结果的 Future 对象
     * Create a new {@link Future} which is marked as succeeded already. So {@link Future#isSuccess()}
     * will return {@code true}. All {@link FutureListener} added to it will be notified directly. Also
     * every call of blocking methods will just return without blocking.
     */
    <V> Future<V> newSucceededFuture(V result);

    /**
     * 创建异常的 Future 对象
     * Create a new {@link Future} which is marked as failed already. So {@link Future#isSuccess()}
     * will return {@code false}. All {@link FutureListener} added to it will be notified directly. Also
     * every call of blocking methods will just return without blocking.
     */
    <V> Future<V> newFailedFuture(Throwable cause);

3.OrderedEventExecutor

public interface OrderedEventExecutor extends EventExecutor {
}

4. EventLoop

public interface EventLoop extends OrderedEventExecutor, EventLoopGroup {
    @Override
    EventLoopGroup parent();
}

5.AbstractEventExecutor

5.1构造函数

    protected AbstractEventExecutor() {
        this(null);
    }

    protected AbstractEventExecutor(EventExecutorGroup parent) {
        this.parent = parent;
    }